CHAP. IX.] 



THE CONTRACTILE TISSUES. 



395 



TOTAL EXCRETION OF NITROGEN BY THE URINE IN THE PERIODS 

 INDICATED, IN GRMS. 



Conclu- 

 sions. 



It will be seen that there is (1) a slight augmentation 

 of the nitrogen excreted during perfect repose as com- 

 pared with periods of light occupation (i. e. 19 '132 grms. per diem, as 

 against 17'857 and 17'612 grms.) ; and (2) that, after the period of 

 hard labour there is an enlarged excretion of nitrogen in the urine 

 which may continue for several days. 



The observations of Edward Smith 1 upon prisoners at 

 ments of ~Ed- hard labour, which were published shortly after the experi- 

 ward Smith. ments of Voit, and before those of Eick and Parkes, 



tend to the same conclusions. 



In an alternating series of days of hard and light labour, with a fixed 

 diet, the average excretion of urea on the days of labour was not indeed 

 markedly greater than on the days of comparative rest. Nevertheless, the 

 excretion of urea underwent from day to day a succession of oscillations 

 which beyond a doubt had reference to the character of the daily labour. 

 In most cases the total excretion of nitrogen during a day of hard labour 

 was somewhat greater than that of the days of light labour just before and 

 just after it; but in some cases it was apparent that the elimination of 

 nitrogen had been held over until the day after labour, making the excretion 

 of that day unusually large, and destroying the value of the averages. 



The general fact of an increased excretion of nitrogen 

 mentso? Flint during periods of hard labour is also supported by the 

 and Pavy. observations of Austin Flint, Jun. 2 , and of Pavy 3 , made 



upon the celebrated pedestrian Weston. This man was 

 kept under observation on two separate occasions during the performance 

 of extraordinary feats of walking, lasting for five or six days; and not 

 only was he observed during the days devoted to walking, but for five 

 or six days before and after. The ingested food in these periods was 

 accurately weighed, and the nitrogen estimated from the tables of Pay en 4 



1 Ed. Smith, " On the Elimination of Urea and Urinary Water." Phil. Trans. Roy. 

 Soc. Lond., vol. cli. pt. iii. p. 747. 1862. 



2 Austin Flint, Juu., New York Medical Journal, June, 1871. " The source of 

 muscular power, as deduced from observations upon the Human Subject under conditions 

 of Kest and of Muscular Exercise." Journal of Anat. and Physiol, Vol. xn. p. 91, 

 1878 (contains the same facts as the former article). 



3 F. W. Pavy, "The effect of prolonged muscular exercise on the system," Lancet, 

 London, 1876, Vol. i. pp. 319, 353, 392, 429, 466 ; Vol. n. pp. 741, 815, 848, 887. 



4 Payen, Substances Alimentaires. Paris. 



